Saudi Arabia will begin enforcing a law that allows only females to work in lingerie and apparel stores, despite disapproval from the country's top cleric.

The 2006 law banning men from working in female apparel and cosmetic stores has not been implemented up to now, partly because of view of hardliners in the religious establishment, who oppose the idea of women working where men and women congregate together.

Saudi women – tired of dealing with men when buying underwear – have boycotted lingerie stores to pressure owners to employ women. Law enforcement starts on Thursday.

The kingdom's religious police enforce Saudi Arabia's strict interpretation of Islam, which prohibits unrelated men and women from mingling. Women and men in Saudi Arabia remain highly segregated and are restricted in how they are allowed to mix in public.

The separation of men and women is not absolute. Women in Saudi Arabia hold high-level teaching positions in universities and work as engineers, doctors, nurses and a range of other posts.

The strict application of Islamic law forced an untenable situation in which women, often accompanied by uncomfortable male relatives, have to buy their intimate apparel from men behind the counter.

Over the past several weeks, some women have already begun working in the stores. Although the decision affects thousands of men who will lose their sales jobs, the labour ministry says that more than 28,000 women, many of them migrants, have already applied for the jobs.

"The employment of women in stores that sell female apparel and a woman standing face to face with a man selling to him without modesty or shame can lead to wrongdoing, of which the burden of this will fall on the owners of the stores," he said, urging store owners to fear God and not to compromise on taboo matters.